Block-signal system.



L. A. HAWKINS.

BLOCK SIGNAL SYSTEM.

APPLIGATION FILED JULY 14.1908.

Petented Feb. 3, 1914.

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BLOCK SGNAL SYSTEM.

APPLICATION FILED JULY 14, 1908.

Patented Feb. 3, 1914.

2 SHEETS-SHEET 2,

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yUNITED STATES PATENT oFFToE.

LAURENCE A. HAWKINS, OF SCHENECTADY, NEW YORK, ASSIGNOR,l BY MESNE AS- SIGrNlllIIENTS,v TO THE UNION SWITCH AND SIGNAL COMPANY, A CORPORATION OF PENNSYLVANIA.

BLOCK-SIGNAL SYSTEM.

Patented Feb. 3, 1914.

Application filed July 14,1908. Serial No. 443,475.

To all 'whom it may concern:

Be it known that I, LAURENCE A.' HAW- KINs, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Block-Signal Systems, of which the following is a specification.

My invention relates to block signal systems, and particularly to signal systems of the normal danger type.

The object of my invention is to provide an efficient and reliable system of this character having a minimum amount `of apparatus and few line wires. y

In a normal danger system employing home and distant signals, or their equivalent, to indicate danger, caution and clear, it is desirable that if the two blocks ahead of' a train are not occupied, the home signals for both blocks should be clear as well as the distant signal immediatelyy ahead of the train and controlled by the home signal in advance. That is, three signals should be cleared; the clearing of the distant signal depending uponv the clearing of the home signal in advance and the clearing of the home signal in advance depending upon the clearing of the home signal immediately ahead of the train. To obtain these operations in proper sequence with a minimum number of line wires, a number of systems have been proposed heretofore, many of which involve the use of a large number of relays. By my invention I am enabled to reduce the number of line relays, that is, re-

lays other than track relays, to two per block. I accomplish this by the use of polarized relays and by certain novel connections.

4@ne feature of my invention consists in a novel arrangement for reversing the current in a circuit to actuate a polarized relay therein. This arral'igement consists in providing a source of voltage for first sending a current through the circuit in one direction and then introducing in shunt to a portion of the circuit a second source of voltage higher than, and in opposition to, the first, so that the direction of the current is reversed without opening the circuit. Furthermore, by this means I am enabled to reverse the current in a line wire without reversing the current in a polarized relay con nectmilr to one end of the line wire and in series with it.. This will be further explained hereafter.

. Another feature of my invention consists in a novel interconnection of the polarized relay and non-polarized or neutral relay. Where neutral and polarized relays have been connected in series and a ,reversal of current has been employed to actuate, the polarized relays, it has heretofore been necessary to resort to specialdesigns of the neutral relay in order. to prevent it from v dropping its armature while the current is reversed. I ayoid the necessity ofl such special designs by arranging the front contacts of the polarized relay to shunt the front contacts of the neutral relay, so that it is only necessary that the neutral relay should be slow acting so that the polarized relay may close its front contacts, thereby shunting the front contacts ofthe neutral relay, before thc front contact of the neutral relay has time to reopen. The difference between slow acting and quick acting relays is well understood in the art, and to produce either action requires no unusual design.

Another feature of my invention, which enables me to reduce the number of relays, consists in providing certain relays with two windings, either of which is adapted to actuate the relay, and connecting those two windings in different circuits which are alternately but not simultaneously closed. The relay responds to each Winding in turn as though the other winding was not present, and the same results are obtained with one relay thus arranged as with two ordinary relays.

My invention further comprises other fea tures of novelty which will best be understood by reference to the accompanying drawings, in which- Figure 1 shows diagrammatically in its preferred form a signal system arranged in accordance with my invention, while Fig. 2 shows a modification of the system.

Referring to Fig. 1, A, A1 and A2 reprev sent the rails of three successive blocks of a block signal system, the direction of travel beingr as indicated by the arrow.

B1 and B2 represent the track batteries for blocks A1 and A2.

(l, (l and C2 represent t-heltrack relays for the three blocks. Each track relayhas four Contact, fingers c to c3.

D1, D2 and D2 represent line relays which are nonpolarized and slow acting.

E1, E2 and E2. represent quick v acting polarized relays. Each of these latter relays has two windings e and e1 which are connected in different circuits and either of which when energized with current in the proper direction will operate the relay. y

F1, F2 and F1 represent home signals, each of which is arranged to actuate a contact f. The connections between these signals and these contacts are indicated diagrammatically by dotted lines.

G1, G2 and G11 represent distant signals.

H1, H2 and H1 represent sources of current, indicated as batteries. In addition to its end terminals each battery has two intermediate terminals k and k1. The four `terminals are represented'as equally spaced; one-third of the total number of cells in' the battery being included between each pair of adjacent terminals.

I represents a return wire common to all signal circuits.

J1 and J 2 represent line wires extending through blocks A1 and A2, respectively, each forming with the common return wire I and the relay winding connections a single normally open circuit for each block.

The parts of the system are shown in the positions they occupy when all the blocks are clear. All the circuits, except the track circuits, are open and all the signal apparatus, except the ytrack relays, are denergized. If a train is in block A, the track relay C is denergized and drops its contact fingers. A circuit is thereby closed from intermediate terminal h of battery H2 through the winding e of relay E2, contact finger c and front contact of relay C1, line wire J1, neutral relay D1, contact finger 02, and back contact of relay C, winding e1 of relay E1, common return wire I to terminal h1 of battery H2. One-third of battery H2 is thus connected in series with polarized relays E1 and E2 and neutral relay D1. The connections of the `relay windings e and e1 of each of' the polarized relays are so shown in the drawing that if the upper terminals of t-he batteries be considered positive, it may be assumed that current passing through the relay windings in the direction of traffic will energize the polarized relays, while current in the opposite direction will not affcc-t them. This being the case it will be seen that relay E2 is energized, while relay E1 is not affected. Relay D1 is, of course, ener-` gized. The shifting of the contact fingers of relays D1 and E2 results in clearing home signals F1 and F2. rl`he circuit for signal F1 may bc traced from'the upperterminal of battery H1, through the contact finger of relay D1. through the operating mechanism of signal F1, to the lower terminal of battery H1. The home signal F1 is consequently cleared. The clearing of home signal F2 is brought about in the following manner: Relay E2,- has been energized as above pointed out. Theshifting of its contact fingers closes a circuit fr m the upper'terminal of battery H2, throlgh the upper contact finger of relay E2, front contact and contact finger c2 of relay C1, neutral relay D2, line wire J2, front contact and contact finger c of relay C2 (block A2 being unoccupied), winding e of polarized relay E3, terminal h of battery H2, through two cells of this battery to terminal h1, line wire I to terminal h1 of battery H2. Four cells of battery H2 are consequently thrown into circuit with, and in opposition to, two cells of' battery H2', so that the direction of flow to line wire J2 is in the opposite direction to the current flow in line wire J 1. Polarized relay E3 is consequently not energized. Neutral relay D2 is however energized and closes a circuit through battery H2 and the operating mechanism -ofr home signal F2. Home signal F2 is, therefore, cleared and in clearing closes its contact This contact connects the lower terminal of battery H2- with line wire J1 through contacts c and c1 of relay C1. A branch circuit is therefore closed around winding e of relay E2, which branch circuit includes the two lower cells of battery H2. This branch circuit includes no resistance other than the resistance of the wires and contacts, but the other branch includes the resistance of winding e of relay E2; and since the two portions of battery H2 included in these two branches are of equal potential, the current from the two lower cells will predominate in the main circuit. But this current flows in the direction reverse to that of the current from the cells between points h and h1, hence the direction of flow of current through relay D1 and winding e of relay E1 is reversed and relay E1 is therefore so energized as to close its front contacts. It will be noted that the direction of flow of current through winding e of relay E2 remains unchanged hence this relay is unaffected'.

Relay D1 may drop its contact finger and pick it up again withoutopening the circuit of home signal F1, provided the action of relay D1 is slow enough to permit relay E1 to close its contacts before relay D1 opens` its contacts. The reason for this is that the upper contact finger of relay E1 is connected through contact. finger c2 and back contact of relay C in shunt to the contacts of relay D1, so that it forms a maintaining circuit for home signal F1. At the same time the circuit of distant signal G1 is closed as follows: from the u per terminal of battery H1, "through the ower Contact fingers ofrelay E1, to the operating mechanism of .signal G1, back contact and contact finger c1 of relayl C, contact f of F1, to lower terminal of battery H1. The distant signal G1 is, therefore, cleared. Thus with a train in block A and blocks A1 and A2 unoccupied, home signalsF1 and F2 and distant signa-l G1 are clear.y When the train enters block A1, it short-circuits track relay C1 and this relay at its contact c opens the circuit of relays E1 and D1 and puts signals F1 and G1 to danger. Home signal F3 and distant signal G2 are then cleared as has already been described for signals F2 and G1.

Fig. 2 shows a modification of the system. This modification in some respects is inferior to the arrangement of Fig. 1, since it necessitates a. special construction of the neutral relays such that they will not drop their contact fingers upon a quick reversal of current flow and also since it renders available for the first operation of the relays only one-sixth of the total battery voltage instead of one-third as in Fig. 1. The modification, h owever, illustrates a further extension of the principle utilized in the system of Fig. 1 for reversing the direction of current flow in the circuit, that is, inserting in 'the circuit a higher opposing voltage.v and the special construction of the neutral relay is not a serious disadvantage, for such special constructions are now well known in the art. (See, for instance, Patent No. 799,816, issued to H. E. White, September 19, 1905.)

In Fig. 2 as in Fig. l the parts are all shown in the positions they occupy when all Ythe blocks are clear. A train entering block A'would denergize relay C and close a circuit from terminal n.1 of battery H2, through the back contacts of contact f on signal F2, through contact fingerc of relay C1, winding e1 of polarized relay E2, line wire J1, neutral relay D1, winding e of polarized relay E1, contact fingers 01 and c2 and back contacts of relay C, upper finger and back contact of relay D1, common wire I, and the lowest terminal of battery H2. It will be noted that the number of cells of each .bat-

tery between adjacent terminals are, beginning at t-he bottom, one, two and three. One cell of battery H2 is thus-connected in series with relays E2, D1 and E1. The direction of current flow in both polarized relays is such as not to operate them. Neutral relay D1 is, however, energized and its lower contact finger closes a circuit through battery H1 and the operating mechanism of home signal F1. Its upper Contact finger in rising opens its back contact. so that the current flowing through the relays E1 and D1 now passes to common return wire I through resistance .A1, and when the contact finger reaches its front contact it closes another circuit which may be traced as follows: from terminal L of battery H1, through the front contact and upper finger of neutral relay D1, back contacts and contact fingers c2 and c1 of relay C, winding e of relay E1,

neutral relay D1, line wire J1, winding e1 of relay E2, front contact and finger c of relay C1, back contacts of contact f of signal F2, terminal k1 of battery H2, through one cell of that battery and through line wire I tov the lowest terminal of battery H1. Three cells of battery H1 are thus thrown in opposition to one cell of battery H2 so that the direction of current flow through line wire J1 and through relays E1, D1 and E2 is reversed. It will be noted that resistance k1 is also connected across the three lower cells of battery H1; this resistance being thrown into circuit to avoid short-circuiting of the battery. The reversal of current in relay D1 as has been said does not cause this relay to open its contact, 'but this modification of this system is designed so as to stand a quick reversal of current without dropping its contact fingers.

Relays E1 and E2 are both operated by the current reversal. The operation of relay E1 produces no useful effect. The operation of relay E2, however, results in clearing home signal F2 provided block A2 is unoccupied. The circuit that produces this effect may be traced as follows: from the terminal k1 of battery H3, through back contact f of signal F3, front contact and contact finger c of relay C2, winding e1 of polarized relay E3, line wire J2, neutral relay D2, front contact` and contact finger c1 of relay C1, lower contact of relay E2, resistance L12 to common line wire I. One cell of battery Ha is thus connected in series with relay E3, relay D2 and resistance k2. Neutral relay D2 conse quently lifts its contact fingers, closing the circuit of the operating mechanism of signal F2. function, since its circuit is open at back contact of contact finger c2 of relay C1. Vhen signal F2 clears, its contact f closes a new circuit which may be traced as follows: from the upper terminal of battery H2, contact f of signal F2, upper contact of polarized relay E2, contact finger c2 of relay' CA to the connection between the front contact of that relay finger and line wire J1. Here the current divides, part passing through winding e1 of relay E2 and contact finger c of relay C1, through resistance K2 to termi nal h1 of battery H2 so that relay winding e1 and resistance K2 are thrown in series across five cells of battery H2, the. current flow of relay winding not being reversed. Resistance K2 is inserted in circuit merely to reduce the flow of current and is not essential. The other part of the current passes through line wire J1. neutral relay D1, winding e of polarized relay E1, cont-act finger 01 of relay (I. resistance '1, line wire I to the lowestterniinal of battery H2. Six cells of battery H2 are thus thrown into opposition to three cells of battery ll1 and the current through relays D1 and E1 is, therefore, again re- Its upper contact finger performs no versed, throwing relay E1 back to its original position. Home signal F1 has been cleared and a circuit is therefore closed from upper terminal of battery H1, contact f of signal F1, back-contacts and upper contact finger of relay E1, o erating mechanism of at the front contacts and upper .contact inf gers of relay E2 and at contact finger c3 of relay C1 so that relay D1 is denergized, putting signal F1 to danger, whichin turn puts distant signal lG1 to danger by opening contact f.V

' Other'modifcations of my system will be obvious to those skilled in the art, and consequently I do not desire to limit myself to the particular connections and arrangement of parts here shown, but aim in the appended claims to cover all modifications which are within lthe scope of my invention.

WhatI claim as new and desire to secure by Letters Patent of the United States', is-

1. In .a block signal system, a line wire extending through a block, a slow-acting neutral relay and a quick-acting polarized relay in circuit with said line wire, the polarized relay having front contacts connected in shunt to front contacts of the neutral relay, means for sending current through said line Wire in a direction to operate the neutral relay. only.4 means for reversing the directionl of current flow in said line Wire, and signals adapted to indicate danger," caution and clear controlled by said relays.

2. In a normal danger block signal system a track relay for each block, a normally-open circuit for each block section each circuit including a line wire extending through the block section and each circuit arranged to be closed when the track relay for that block is energized and the track relay for the preceding block is denergized, aneutral relay winding and a polarized relay winding included in said circuit at the entrance of the block, a polarized relay winding included in said circuitat the exit end, signals controlled by said relays, a source of current adapted, when said circuit is closed, to send through it a current in al direction to energize the polarized relay at the exit end but not the other, means controlled by the polarized relay at the exit end for closing the circuit for the block in advance and sending. through it a current in opposition to the voltage of the source'in that circuit, a branch around the polarized relay at the exit end of each circuit which branch in,d

cludes a second source of current of opposite polarity and means controlled by the signal for the block in advance for opening and closing said branch thereby reversing the flow of current in the circuit for the firstmentioned block but not in the polarized relay winding at its exit end.

3. In a normal danger block signal system, a track relay lfor each block, a n ormally-open circuit for each block section each circuit including a line lwire extending through the block section and each circuit arranged to be closed when the track` relay for that block is energized and the track relay for the preceding block is denergized, a neutral relay winding and a olarized relay winding' included in said circuit at the entrance of the block, a polarized relay winding included in said circuit at the exit end, signals controlled by said relays, a source of current in said circuit, means controlledby the. polarized relay at the exit end for closing the circuit for the block in advance, a branch around the polarized relay at the exit end of each circuit which branch includes a second source of current of opposite polarity and means controlled bythe signal for the block in advance for opening and closing said branch thereby re- Versing the flow of current in Ithe circuit forthe first-mentioned block but not in the polarized relay at the exit end.

4. In a railway signaling system, a plurality of block sections, a polarized line relay for each block section, sources of current of different voltage for each block section, a circuit for each block section extending through the section and including a winding of the polarized relay and one source of current for the block sect-ion next in advance, and a circuit controller included in each of said circuits for introducing into such circuit a winding of the polarized re-V lay of the corresponding block section or a source of current of a different voltage for the corresponding block section according as the circuit controller is in one position or another, and signals controlled by said polarized relays. l

5. In a railway signaling system the combination of a plurality of block sections, a track relay for each blockl section, a polarized line relay for each block section, sources of current of two voltages for each block section, a circuit for each block sect-ion eX- tending through the section and including a winding of the polarized relay and a source of current of one voltage for the block section next in advance, and a circuit controller in each circuit and included in the track relay for the corresponding block section for introducing into said circuit a winding of the polarized relay of the corresponding block section or the source of current of the other voltage for the said corresponding block section according as the circuit controller is in one position or ahother, and signals controlled by said polarized relays 6. In a railway signaling system the combination of a plurality of block sections, a track relay for each block section, a polarized line relay for each blc-ck section, sources of current of two voltages for each block section, a circuit for each block section extending through the section and including a winding of the polarized relay and a source of current of .one voltage for the block section next in advance, and a circuit controller in'each circuit and included 'in the track relay for the corresponding block section for introducing into such circuit a winding of the polarized relay of the corresponding block section or the source of current of the other voltage for the` said corresponding block section accordingas the circuit controller is in one position or another, and a circuit controller operated by cach track relay and included 1n the circuit for the corresponding block section, and signals controlled by said polarized relays.

7. In a railway signaling system the combination of a plurality of block sections, a track relay for each block section, a polarized line relay and a neutral line relay for each block section, sources of current of two voltages for each block section, a circuit for each block section extending through the section and including a winding of the polarized relay and a source of current of one voltage for the block section next in advance and the winding of the neutral relay for the corresponding block section, a circuit controller included in each circuit and operated b the track relay for the corresponding b ock section for introducing into such circuit a winding of the polarized relay of the said corresponding block section or the source of current of the other voltage for the corresponding block section according as the circuit controller is in one position or another, and signals controlled by the said line relays.

8. In a railway signaling system the combination of a plurality of block sections, a track relay for each block section, a polarized line relay for each block section, sources of current of two voltages for each block section, a circuit for each block .section extending through the section and including a winding of the polarized relay and a source of current of one voltage for the block section next in advance, a circuit controller included in each circuit and operated by the track relay for the corresponding block section for introducing into such circuit a Windo ing of the polarized relay of the corresponding block section or the source of current of the other voltage for the said corresponding block section according as saidy c1rcu1t controller is on one position or another, a

35 circuit controller operated by each polarized relay and included in the circuit for the corresponding block section forl controlling said circuit when said circuit includes the second-mentioned source of current, and signals cont-rolled by said polarized relays.

9. In a railway signalin system, the combination of a plurality o block sections, a track relay for each block section, a neutral line relay and a polarized line relay for each block section each polarized relay having two windings, sources of current of two voltages for each block section; a circuit for each block section extending through the section and including a source of current of one voltage and a winding of the polarized relay for the block section next in advance and the winding of the neutral relay for the corresponding block section, and a circuit controller included in each circuit and operated by the track relay for the corresponding block section for introducing into such circuit the other winding of the polarized relay for the corresponding block section or the source of current of the other voltage for such corresponding block section according as the circuit controller is in one position or another, and signals controlled by the said line relays.

10. In a railway signaling system the combination of a plurality of blocksections, a track relay for each block section, a polarized line relay for each block section each having two windings, sources of current of two voltages for each block section, a circuit for each block section extending through the section and including a source of current of one voltage and a winding of the polarized relay for the section next in advance, and a circuit controller included in each circuit and operated by the track relay for the corresponding block section for introducing into such circuit the other winding of the polarized relay for the corresponding block section or the source of current of the other voltage for such corresponding block section according as the circuit controller is in one position or another, and signals cont-rolled by said polarized relays.

11. In a railway signaling system the combination of a plurality of block sections, a polarized line relay for each block section each having two windings, sources of current of substantially equal potential but opposite polarity for each block section; a circuit for each block section each including one source of current and a winding of the polarized relay, at the exis end of the block section, and the other winding of the polarized relay at the 'entrance ofthe block section; a branch circuit around the first mentioned winding yof the polarized relay at the exit end of the 'section which branch includes the other adjacentv scarce o'f current, and means for controlling said branch circuit whereb the direction of flow of current through 133 the winding of the polarized relay at the entrance end of the block section may be reversed'.

12. In a railway signaling system the combination of a plurality of block sections, a polarized line relay for each block section each having two windings, sources of current of substantially equal potential but opposite polarity for each block section; a circuit for each block section kkeach including one source of current and a winding of the polarized relay at the exit end of the block section, and the other Winding of the polarized relay at the entrance end of the block section a branch around the first mentioned winding of the polarized relay at the exit end, which branch includes the other adjacent source of current, a home signal for each block section, means include-d in the said circuits for controlling said signals, a circuit controller operativel connected with each home signal and inclu ed in the said branch for the circuit of the block section next in rear of said home signal for controlling said branch whereby'the direction of flow of current in the polarized relay at the entrance end of the block section may be reversed, and a distant signal controlled by each polarized relay.

13. In a railway signaling system a plurality of block sections, a polarized line rela for each block section each having two wlndings, sources of current of substantially equal potential and opposite polarity for each block section; a circuit for each block section each comprising one source of current and a winding of the relay at the exit end of the block section, and the other winding of the relay at the entrance end of the block section; a branch around the firstmentioned winding of the relay at the exit end each branch including the other adjacent source of current, and means for controlling each branch whereby the direction of How of current through the winding of the relay at the entrance end of the block section may be reversed.

In witness whereof, I have hereunto set my hand this 13th day of July, 1908.

LAURENCE A. HAWKINS.

Witnesses:

HELEN ORFORD, BENJAMIN B. HULL. 

